this cake is amazing! my family devoured it so quickly that i made two in 24 hours. but both times, the center of the cake fell and was gooier than the edges. i think it's because i baked it in a pyrex glass dish instead of a metal pan. i even tried reducing oven temperature by 25 degress the second time around, but the same thing happened. before i invest in a new baking pan... any idea if there's something else that could be going wrong or do i just need to switch to metal? (also, i'm supposed to bake this conventionally, and not convection, right?) thanks!